It has been possible to use an IC card for an identification card, a membership card, or a patient's registration card. A writable/readable area can be included in an IC card. It has been possible to receive/send or share information by writing information on an IC card by a certain organization and by reading the information from the IC card by an IC card owner or another organization. The patent document 1 discloses a system in which a certain medical institution writes medical information on an IC card of a patient and another medical institution can refer to the medical information.    Patent Document 1: JP2000-285189